Update to Libtool 2.2.6b and use LT_INIT instead of
AC_PROG_LIBTOOL. Update to Autoconf 2.65 and Automake 1.11.1.
Replace the obsolete AC_TRY_COMPILE by AC_COMPILE_IFELSE
in the mkdir() macro example.

Jack Kelly suggested using foreign -Wall-Werror instead of
-Wall-Werror foreign because the foreign option may alter
the -W settings. Lorenzo Bettini pointed out that HP's test
drive had been closed, so I'm now suggesting to Google for "free
shell account" instead of pointing to specific services. Laurent
Lyaudet reported several typos. Nicolas Cherel suggested to
highlight a change in an example, because he did not notice it on
first read.

Some remarks from Ralf Wildenhues: the important change is that
the tutorial now always puts libraries in _LDADD or
_LIBADD, even -l and -L options. The position of _LDFLAGS
on the link line doesn't make it appropriate for static
libraries; it is better used for other link options.

Akim Demaille caught a few errors, and bundled them with more
suggestions. Two noteworthy improvements in this new version,
based on his suggestions: display the new lines in the M4
example, and split the definition of AX_FUNC_MKDIR_ONE_ARG in
two macros (one for the test and the other for the caching and
definitions).

Use #include <config.h> instead of #include "config.h" as
suggested by the Autoconf manual and pointed out by Florian Stoehr.
Upgrade to Gettext 0.14.5, Libtool 1.5.22, and Automake 1.9.6
(no change needed).

Upgrade the drawing macros used in the LaTeX source to the brand
new version 1.00 of pgf (the graphic package that comes with
beamer). The change was hard since I couldn't find how to define
the control points of the curved arrows in the same way as in
version 0.67, but the resulting source is now much more readable.

Autotools versions are displayed at the very beginning, (1) to invite
newcomers to start with up-to-date tools, and (2) to help people
judge when the tutorial has become obsolete.

Added a slide, Lost?, at the end of Part 2, following an
advice read in Mathematical Writings (Donald E. Knuth, Tracy L. Larrabee, and Paul
M. Roberts):

Don's wife commented that one thing she always needs to know is
“How do I get out of a mess if I do something wrong?” Don said
that this is something manuals almost never explain—perhaps it
never occurs to their authors that somebody will eventually want
to stop playing with their program.

(Although completely unrelated to Autotools, Mathematical Writings is pleasant and
instructive reading. You can find a PDF version of the initial
report on-line.)

Do not use aclocal -I m4 in the Libtool example. This is only
useful for the upcoming Libtool 2.0, and would cause distcheck
failures in this little example (can't use AC_CONFIG_AUX_DIR with
an empty directory).

Since this page has been mentioned a few times already, it's time to
start a ChangeLog so people know what changed. Let me also thank
Akim Demaille, Jim Meyering, Karl Berry, and Noah Misch
for comments and corrections on earlier versions (I started working
on this on 2004-12-12).